Problem: In his physics class, Christopher took 5 exams. His scores were 88, 79, 78, 84, and 76. What was his average score on the exams?
Explanation: The average is the sum of his scores divided by the number of scores. There are 5 scores and their sum is $88 + 79 + 78 + 84 + 76 = 405$ His average score is $405 \div 5 = 81$.